import { useRef, useEffect } from "react";

// Hook
export function useEventListener(eventName, handler, element = window) {
  // Create a ref that stores handler
  const savedHandler = useRef(null);

  // Update ref.current value if handler changes.
  // This allows our effect below to always get latest handler ...
  // ... without us needing to pass it in effect deps array ...
  // ... and potentially cause effect to re-run every render.
  useEffect(() => {
    savedHandler.current = handler;
  }, [handler]);

  useEffect(() => {
    // Make sure element supports addEventListener
    // On
    const isSupported = element && element.addEventListener;
    if (!isSupported) return;

    // Create event listener that calls handler function stored in ref
    const eventListener = event => {
      if (savedHandler && savedHandler.current) {
        savedHandler.current(event);
      }
    };

    // Add event listener
    element.addEventListener(eventName, eventListener);

    // Remove event listener on cleanup
    return () => {
      element.removeEventListener(eventName, eventListener);
    };
  }, [eventName, element]); // Re-run if eventName or element changes
}